Lots of swell to come, with an XL event for Friday
Hawaii North Shore forecast by Craig Brokensha (issued Tuesday 12th January)
Best Days: Every day over the coming period for experienced surfers (smallest Thursday morning for less experienced)
This week and weekend (Jan 12 - 17)
After a very large pulse of NW groundswell yesterday, a drop in size was seen this morning from the 10ft range, further into this evening.
A reinforcing N/NW groundswell is expected tomorrow, generated by a low on the backside of the progression generating Sunday's swell, with exposed breaks due to offer sets in the 10ft+ range tomorrow morning, easing through the middle of the day.
Later in the day we should see another slightly smaller pulse of N/NW groundswell, peaking through the evening and easing from the 8ft range Wednesday morning.
Light winds with afternoon sea breezes are due tomorrow, Wednesday and Thursday with a slight increase in E/NE trades Friday.
As touched on last update, we've got an XL swell due Friday/Saturday across the region as a vigorous cold front projecting down towards Hawaii from the Kamchatka Peninsula produces a fetch of severe-gale NW winds, for a 'bombing low' to then more over. A 'bombing low' is an intense low pressure system that drops more than 24hpa in central pressure in 24 hours.
An additional fetch of storm to hurricane-force NW winds will be generated by the 'bombing low' over an already active sea state, producing an XL swell for Friday.
Initially the fetch of severe-gale NW winds will generate a large pulse of NW groundswell building later Thursday to at least 8ft by dark, with the XL swell peaking Friday morning in the 15-20ft range across the North Shore, with much larger sets at deep water offshore reefs.
Large waves will continue into Saturday on the backside of the swell as a fetch of severe-gale NW winds remained aimed towards Hawaii on the backside of the low. A slow drop from 15ft+ is expected, further into Sunday.
Generally light variable winds are due over the weekend, with E/NE trades kicking back in from early next week.
Into next week, one final large NW groundswell pulse is likely Monday but we'll have another look at this on Thursday.